1. Field of the Invention
The present invention relates to a biomedical electrode which senses a bioelectric signal when adhering to a surface of living tissue (hereinafter referred to as xe2x80x9cbiological surface tissuexe2x80x9d), and more particularly, to a biomedical electrode which easily follows the motion of biological surface tissue and is less likely to cause inflammation.
2. Related art
A disposable biomedical electrode integrally consisting of an electrode element and adhesive tape for fixing the electrode element on biological surface tissue has bee used widely in the field of, for example, an electrocardiograph. FIG. 7 shows the configuration of an example of a prevailing biomedical electrode.
In FIG. 7, an electrode element 1 is made of Ag/AgCl and consists of a disk 1a and a pin 1b integrally protruding from the center of one surface of the disk 1a. A sponge 3 filled with a conductive gel or paste is bonded to the surface of the disk 1a opposite the surface having the pin 1b provided thereon.
Adhesive tape 4 is formed from nonwoven fabric into a tear-drop shape, a circular shape, or a rectangular shape, and a circular opening 4a is formed in the center of the adhesive tape 4. The disk 1a of the electrode element 1 is inserted into the opening 4a. A disk-shaped label 5 is bonded to one surface of the adhesive tape 4. Further, the pin 1b of the electrode element 1b is inserted into a small hole 5a formed in the center of the label 5. In this state, the electrode element 1 is firmly fixed on the label 5 and adheres to biological surface tissue of a subject by way of a strong adhesive layer formed on the surface of the adhesive tape 4 having the label 5 fixed thereon. As a result, there can be minimized noise, which would otherwise be caused by motion of the subject or swinging of a lead wire connected to the pin 1b of the electrode element 1.
When a biomedical electrode is not in use, the surface of the adhesive tape 4 having an adhesive placed thereon is covered with a gel cover 6, thereby preventing mutual adhesion of biomedical electrodes or drying of gel when the biomedical electrode is to be reserved for a long period of time. The outer dimension of the gel cover 6 is greater than that of the adhesive tape 4, and an indentation 6a is formed in the center of the gel cover 6 for accommodating the sponge 3. When a biomedical electrode is used, the gel cover 6 is detached from the adhesive tape 4, thereby uncovering the sponge 3.
In the prevailing biomedical electrode having such a structure, the adhesive tape 4 is made of nonwoven fabric or foam and has a thickness of 1 mm or thereabouts and is comparatively rigid. If the subject performs unnatural motion, the skin may expand and contract or form a kink, thereby causing warpage between the plastered adhesive tape 4 and the surface of the skin. Particularly, such warpage is likely to arise in the outer circumferential portion of the adhesive tape 4, and a corresponding portion of the skin is liable to suffer inflammation.
The present invention has been conceived in view of such a backdrop and is aimed at providing a biomedical electrode which facilitates handling of a tape for fixing an electrode element on biological surface tissue, enables the tape to easily follow the motion of the biological surface tissue, and prevents occurrence of inflammation in the portion of the biological surface tissue to which the electrode element adheres.
Accordingly, the present invention provides a biomedical electrode including an electrode element which has at one end thereof a conductive gel layer, and tape which retains the other end of the electrode element and is to be plastered to biological surface tissue, wherein the tape is made of a flexible, extendable, and thin film, and a reinforcing cover film for removably covering the side of the tape opposite the surface to be plastered on the biological surface tissue is provided on the tape.
Preferably, extending the tape to a length which is twice the length of the tape when no tension is applied thereto requires a force of 400 grams or less per 1 cm width.
Preferably, the tape has a steam permeability of 400 g/m2/24 hr or more.
Preferably, the tape has a thickness of 0.1 mm or less.
Preferably, the cover film is divided into two sub-sections, and the butt faces of the two sub-sections are butt-joined. The portion of the cover film in the vicinity of the butt-joined portion is not crimped onto the tape.
Preferably, a cut is formed in the cover film from its center to outer edge. A tab tape for removing a cover film is attached to one side or both sides of the cover film with reference to the cut.
Preferably, a tab tape for removing a cover film is attached to the outer edge of the cover film.
Since the tape which retains an electrode element and is to be plastered on biological surface tissue is made of a flexible, extendable, and thin film, the tape can extend so as to follow the motion of the skin stemming from the movement of the subject, thereby preventing occurrence of inflammation in the skin, which would otherwise be caused when strain is applied to the skin. Since a reinforcing cover film is attached to the tape, no kink arises in the surface of the tape, which would otherwise be caused when a thin tape is plastered on the biological surface tissue.
After the tape has been plastered on the biological surface tissue, a cover film is exfoliated by means of the cover film being removed from the tape and from a butt-joined portion of the cover film toward the outside, thus enabling removal of only the cover film without involvement of exfoliation of the tape.
The tab tape for removing a film is picked up and pulled manually toward the outer edge, thus enabling removal of the cover film from the tape.
The tab tape is manually picked up and pulled upward, thus enabling removal of the cover film from the tape.